Database Development
In the world of enterprise application development, Oracle Database has been used to power many of the largest and most demanding systems. It is the primary data source for several mobile banking applications, electronic health records (EHR), online airline booking, claims processing software, telecom provisioning, ERP workflows managing hundreds of thousands of orders, manufacturing/supply chains, e-commerce, multiple government projects, and even global software-as-a-service (SaaS) solutions.
There are many reasons to select Oracle as an organization’s DBMS of choice, including scalability; transactional integrity; high-availability clustering; distributed workload management; and data protection using built-in security policies and procedures.
However, the best designed and implemented database solution will not completely eliminate risk. No matter how reliable a database system may seem, it will still have the potential for facing:
- Disk failure
- Corruption of storage
- Accidental changes to data
- Errors in configuring storage for a deployment
- Ransomware and brute force attacks
- Downtime due to hardware failure in the data center
While Oracle provides excellent backup and recovery solutions to mitigate these risks, the true reliability is determined by the approach used to design, automate, monitor, test, and recover the backups.
A well-designed and implemented strategy for backup/recovery accomplishes four primary objectives:
1. Capturing data in a repeatable way
2. Storing backed-up data in a secure environment
3. Recovering from backup in a timely manner and validating that recovery process
4. Avoiding the restoration of incomplete or corrupted backups
1. Archive Log Mode Is The Initial Step Toward Recovery Preparedness
Every time Oracle performs an action, such as inserting data or updating a table, it records this information in redo logs. If your Oracle database does not archive the redo logs, all transaction history will be lost once the logs are overwritten.
When you switch your Oracle database to ARCHIVELOG mode, you are allowing Oracle to do the following:
- Archive the redo logs to files.
- Retain a record of all changes made to the database.
- Enable you to restore your database to any point in time.
- Restore data blocks based on previous redo log information.
- Enable you to use Flashback technology to undo changes.
- Meet regulatory compliance requirements in an audit-driven industry.
When you switch to ARCHIVELOG mode, you can restore your database to the exact moment before the event causing the database failure, error, or corruption occurred.
If your Oracle database is running in production, ARCHIVELOG mode is essential to have an up-to-date database. If your database is not running in ARCHIVELOG mode, the only point you can return to is the last complete backup of the database. This will result in having a data gap in your records, having inconsistent business operations, having financial reconciliations that are inaccurate, having overlapping rental agreements or sales, and risking non-compliance with regulatory requirements.
2. RMAN is the Most Reliable Backup Solution for Oracle
Oracle has developed and maintains Recovery Manager or RMAN to provide businesses with an easy method of back up/recovery for Oracle databases.
With RMAN, your database can be backed up while in operation with no downtime for your database application.
RMAN allows you to verify each of the backup files created and protects users from the hassle of having to restore unusable file backups.
There are many types of RMAN backups available that meet different Service Level Agreements (SLAs) a business has with its customers:
- RMAN creates a backup baseline of the database at full capacity.
- RMAN is capable of tracking all changes to data blocks since the last backup; RMAN backs up data blocks incrementally for each change made since the previous back up record.
- RMAN compresses backup files to eliminate the need to store all duplicate files and save disk space.
- RMAN is able to restore only the affected data blocks instead of restoring the entire database for every restore job.
- RMAN has an ability to create safe databases for business recovery drills.
- RMAN is capable of automating repetitive tasks through the use of scripts and schedulers.
Oracle has implemented RMAN and the Oracle automated recovery process using three levels of protection:
- Data files.
- Control files (database structural metadata).
- Archive logs (transactional history).
Losing control files means businesses have lost the roadmap available for Oracle to successfully restore data stored to the database. For that reason, RMAN automatically creates control file backup for each RMAN job executed by RMAN.
3. The Basic Storage Hub of Oracle Recovery is the Flash Recovery Area
Oracle maintains a single hub for all recovery-related storage, and that hub is what’s called the “Flash Recovery Area” (FRA).
The FRA stores:
- Master copies of some RMAN backups
- Archive logs
- Flashback logs
- Auto generated control backups
- Index and meta-information sources related to recovery
With all of the storage consolidated, throughout the DBA team environment, you have less chaos because DBA’s find their backups faster and restore quicker as well.
The FRA Needs to Scale:
- Define a limit to the amount of storage available (Oracle will allocate this amount).
- Oracle will continuously write log and backup files to the FRA.
- Monitor the amount of free space in the FRA so that you do not run out of space preventing new transaction usage.
- Schedule clean-up of archived logs after you have completed backing them up.
An FRA is a must-have.
It’s about reliability.
You will experience faultless transactions; as a result of having all of your logs in one place, you will never experience a transaction failure due to a scattered or overwhelming source for log traffic.
4. Flashback is an Instant Undo for your Data
Both start-ups and enterprise-level companies enjoy the ability to use Flashback because of the no-downtime nature of reversing a transaction.
Flashback can help reverse alleged logical mistakes and swiftly restore records from the database.
Flashback Works by:
- Restore of a single row of data by using a previously executed query;
- Restore a table from a deleted status;
- Flashback the entire database to a defined timestamp;
- Utilize the restore function within a recycle bin;
- Restore the original state of stuff by rolling back an invalid update.
An Administrator must configure flashback logs in the FRA before using Flashback. Once this is done, you will experience instant recovery due to user or logical errors.
5. Oracle Data Guard: A Secondary World
The protection of a company begins with the creation of a back-up and a monitoring solution for their database.
The way to protect your business is by replicating your data.
Data Guard will keep an active replica of your database. The replica will be located on another server located near by or in another region.
With Data Guard, you will have:
- An operating store, even if the primary Oracle database goes down.
- Real-time streaming of redo logs to your stand by database.
- Lowered demand on resources because of using your standby database for reads, analytics and/or reports.
- Ability to safely switch workloads during maintenance or upgrade.
- Fast recovery from any downtime caused by infrastructure failure.
- Less risk for reconciliation errors due to Failovers.
Your enterprise must have the ability to replicate and keep resilient across a wide area. Data Guard provides that resiliency while allowing the primary database to continue to operate.
6. Oracle Database Cloud Backup Solutions
The trend toward hosting Oracle DB within the cloud continues to grow. This also adds another layer of protection, but still requires advanced planning and organization.
Cloud infrastructure still supports the continuation of RMAN (Recovery Manager), as RMAN is used for taking backups from your database.
- Cloud storage will still have the backup files which will be stored in an object storage bucket.
- Backup files will still be replicated across multiple regions.
- Cloud Storage will keep your backups secure and encrypted while in object storage.
- You must define retention policies and expiration rules.
- You should run restore drills or testing from a staging node to verify the backups.
Although cloud storage provides durability, it doesn’t replace the strategy, you will need to monitor logs, validate backups, test recovery process, develop disaster plans, and so on.
Oracle uses the following tools to create Backup build safety and Recovery build Continuity in your environment.
The configuration you build with these tools yields the required resilience. The Basic Functions of Recovery and Backup Tools, when implemented correctly, will allow you to use the following functions at some point, in the event of a disaster.
Archive Logs – Point In Time Recovery
- RMAN (Random Module As New) – Validating and Recurring Backup
- FRA – All Recovery Artifacts in a Central Location
- Flashback – Rapid Rollbacks of Human Error
- Data Guard – Recovery from Infrastructure Failures through Replication
- Data Pump – Reliable Export of Database Modules and Schemas
Retention, Monitoring and Restore Drills Guarantee SLAs.
Result of the Above
- No Incomplete Transactions
- No Corrupted Restorations
- No Surprises from Downtime
- No Gaps During Data Reconciliation
- No Overflows, or Missing Storage
- No Failures to Comply with Audit Standards
- No Lags in Rollback Cycles
Using an Oracle database is More than Making Backups
It’s about Consistent, Ongoing Monitoring, Validating, Replaying, Retaining, Restoring to ensure that both your Oracle Database and Business can work together without Fear of Losing Data.
